Deterministic processes drive wetland plant community composition and diversity
C. M. Ciafre
Introduction
Ecological communities are the result of species’ geographic distribution, dispersal capabilities, speciation, environmental filtering, and stochastic events. By definition stochasticic events are random colonization and extinction events that ultimately cause ecological drift. Deterministic processes are non-random environmental processes like environmental filtering, biotic interactions, and niche partitioning. Wetlands isolated in uplands may act as islands, so predictions about stochasticity made by the Theory of Island Biogeography may apply. The following predictions will be tested throughout the Eastern Highland Rim ecoregion:
Wetland size will positively correlate with species richness.
The distance between wetlands will negatively correlate with the similarity of their plant communities.
Differences in plant communities will not significantly differ from a randomly-generated null model.
Methods
Data Collection
Plots were sampled at 27 independent sites throughout a subset of the Eastern Highland Rim ecoregion (delineated in yellow below). Note that some sites were in close proximity, sometimes as close together as 200m apart.
Data was collected for plots using 1 m^2 quadrats, of which there were 1031 total. With a few exceptions, all vascular plant species within each quadrat were identified to the species level. Variables were measured at each site; these include water permanence, early season water depth, late season water depth, water depth change, site area, and land use (grazing).
